kernel/git/stable/linux.git/net/9p/client.c, branch linux-4.17.y

net/9p/client.c: put refcount of trans_mod in error case in parse_opts()

2018-08-24T11:07:10+00:00

[ Upstream commit c290fba8c4ce6530cd941ea14db5a4ac2f77183f ] In my testing, the second mount will fail after umounting successfully. The reason is that we put refcount of trans_mod in the correct case rather than the error case in parse_opts() at last. That will cause the refcount decrease to -1, and when we try to get trans_mod again in try_module_get(), we could only increase refcount to 0 which will cause failure as follows: parse_opts v9fs_get_trans_by_name try_module_get : return NULL to caller which cause error So we should put refcount of trans_mod in error case. Link: http://lkml.kernel.org/r/5B3F39A0.2030509@huawei.com Fixes: 9421c3e64137ec ("net/9p/client.c: fix potential refcnt problem of trans module") Signed-off-by: Jun Piao Reviewed-by: Yiwen Jiang Reviewed-by: Greg Kurz Reviewed-by: Dominique Martinet Tested-by: Dominique Martinet Cc: Eric Van Hensbergen Cc: Ron Minnich Cc: Latchesar Ionkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net/9p/client.c: fix potential refcnt problem of trans module

2018-04-06T04:36:23+00:00

When specifying trans_mod multiple times in a mount, it will cause an inaccurate refcount of the trans module. Also, in the error case of option parsing, we should put the trans module if we have already got it. Link: http://lkml.kernel.org/r/1522154942-57339-1-git-send-email-cgxu519@gmx.com Signed-off-by: Chengguang Xu Reviewed-by: Andrew Morton Cc: David Miller Cc: Eric Van Hensbergen Cc: Ron Minnich Cc: Latchesar Ionkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

net/9p: avoid -ERESTARTSYS leak to userspace

2018-04-06T04:36:22+00:00

If it was interrupted by a signal, the 9p client may need to send some more requests to the server for cleanup before returning to userspace. To avoid such a last minute request to be interrupted right away, the client memorizes if a signal is pending, clears TIF_SIGPENDING, handles the request and calls recalc_sigpending() before returning. Unfortunately, if the transmission of this cleanup request fails for any reason, the transport returns an error and the client propagates it right away, without calling recalc_sigpending(). This ends up with -ERESTARTSYS from the initially interrupted request crawling up to syscall exit, with TIF_SIGPENDING cleared by the cleanup request. The specific signal handling code, which is responsible for converting -ERESTARTSYS to -EINTR is not called, and userspace receives the confusing errno value: open: Unknown error 512 (512) This is really hard to hit in real life. I discovered the issue while working on hot-unplug of a virtio-9p-pci device with an instrumented QEMU allowing to control request completion. Both p9_client_zc_rpc() and p9_client_rpc() functions have this buggy error path actually. Their code flow is a bit obscure and the best thing to do would probably be a full rewrite: to really ensure this situation of clearing TIF_SIGPENDING and returning -ERESTARTSYS can never happen. But given the general lack of interest for the 9p code, I won't risk breaking more things. So this patch simply fixes the buggy paths in both functions with a trivial label+goto. Thanks to Laurent Dufour for his help and suggestions on how to find the root cause and how to fix it. Link: http://lkml.kernel.org/r/152062809886.10599.7361006774123053312.stgit@bahia.lan Signed-off-by: Greg Kurz Reviewed-by: Andrew Morton Reviewed-by: Yiwen Jiang Cc: Eric Van Hensbergen Cc: Ron Minnich Cc: Latchesar Ionkov Cc: David Miller Cc: Laurent Dufour Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

9p: Fix missing commas in mount options

2017-11-19T22:31:06+00:00

Since commit c4fac9100456 ("9p: Implement show_options"), the mount options of 9p filesystems are printed out with some missing commas between the individual options: p9-scratch on /mnt/scratch type 9p (rw,dirsync,loose,access=clienttrans=virtio) Add them back. Cc: stable@vger.kernel.org # 4.13+ Fixes: c4fac9100456 ("9p: Implement show_options") Signed-off-by: Tuomas Tynkkynen Signed-off-by: Al Viro

net/9p: Switch to wait_event_killable()

2017-10-24T03:10:01+00:00

Because userspace gets Very Unhappy when calls like stat() and execve() return -EINTR on 9p filesystem mounts. For instance, when bash is looking in PATH for things to execute and some SIGCHLD interrupts stat(), bash can throw a spurious 'command not found' since it doesn't retry the stat(). In practice, hitting the problem is rare and needs a really slow/bogged down 9p server. Cc: stable@vger.kernel.org Signed-off-by: Tuomas Tynkkynen Signed-off-by: Al Viro

9p: Implement show_options

2017-07-11T10:08:58+00:00

Implement the show_options superblock op for 9p as part of a bid to get rid of s_options and generic_show_options() to make it easier to implement a context-based mount where the mount options can be passed individually over a file descriptor. Signed-off-by: David Howells cc: Eric Van Hensbergen cc: Ron Minnich cc: Latchesar Ionkov cc: v9fs-developer@lists.sourceforge.net Signed-off-by: Al Viro

net/9p: switch to copy_from_iter_full()

2017-04-21T17:57:22+00:00

Signed-off-by: Al Viro

p9_client_readdir() fix

2017-04-17T18:23:20+00:00

Don't assume that server is sane and won't return more data than asked for. Cc: stable@vger.kernel.org Signed-off-by: Al Viro

Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-03-04T05:44:35+00:00

Pull misc final vfs updates from Al Viro: "A few unrelated patches that got beating in -next. Everything else will have to go into the next window ;-/" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: hfs: fix hfs_readdir() selftest for default_file_splice_read() infoleak 9p: constify ->d_name handling

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:29+00:00

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar